Tuesday, December 29, 2015

More about the hot weather in North America, and more

In the comments today, under the article about the extreme weather around the world these past few days, there was a claim that "It was warmer in the US in 1955". There was nothing else except a link to two maps of the USA. The top map was labeled 2015 and the bottom map was labeled 1955. The maps were coloured but there was:

no legend

no date

no information that would explain anything about what the charts were meant to represent.

That sort of behaviour is more common on denier blogs than it is here at HotWhopper. Anyway, it prompted me to do some reading and research, and in the process I got diverted a bit into US temperature records, and trends in diurnal temperature range. So this article is a bit of a wander, and a bit long.

How hot was it in 1955 in the USA?

First, though, let's see about the very short and somewhat cryptic comment from HotWhopper reader, Andy Wilkins. He wrote that it was warmer in the US in 1955. But was it? No, it wasn't. At least not if you are looking at mean annual surface temperatures.

Below is a chart showing the annual mean surface temperature for the contiguous USA from 1895 to 2015 (average to November). I've marked the mean temperatures for 1955 and 2015, and this year so far is1.31 °C hotter than the annual mean temperature in 1955.

Now if Andy had somehow mistaken 1955 for 1954, then the difference between then and now would have still been 0.41 °C . That is it's been 0.41 °C hotter this year so far than it was back in 1954. (Note: The US temps and chart were corrected shortly after posting.)
I dug a bit deeper into Andy's comment, which took me around deniersville. I found myself tripping from the blog of a UK denier to a video from a US denier. The image that Andy linked to turned out to be from a YouTube video from Joe Bastardi, the science denying weather forecaster from Weatherbell. He's the chap who four years ago said that we are heading for mini ice age. Oops!

Anyway, here is the basis for the claim that it was hotter in 1955 in the USA. It's a map of the NCEP/NCAR Reanalysis of temperature around North America for 24 December in 1955 and 24 December in 2015. I've animated it to show the same day for both years. Yes, it's just a day - not the whole year.

There is a huge blob of very cold air over the north west in 1955, which is smaller and warmer in 2015. There's also a big blob of cold air to the east that isn't there this year. The red blob of warm air is also bigger and positioned differently in 2015 than it was in 1955. It stretches right the way up to the Arctic this year. In 1955 it was positioned over the middle of the USA. More of the contiguous USA (not including Alaska) was warm, but in different parts to this year. Averaged overall, though, North America and its surrounds were warmer this Christmas Eve than in 1955.

By the way, the image that Andy linked to had a lot of the cold bits cropped out from 1955 and warm bits cropped out from 2015. Here it is, so you can compare it to the images from Joe Bastardi's video as shown just above:

I wonder if what Andy was trying to say was that there was nothing unusual about the temperatures in the USA recently, despite the records being broken. And despite the fact that Joe Bastardi had to trawl all the way back to 1955 to even get close to the recent temperatures - and he could still only find one day! Even then the denier map had to chop off the surrounding regions, because they spoilt the story. (Or maybe he was wanting to say that climate science is a hoax because ... Christmas Eve.)

To complete the 1955 to 2015 picture, here is an animation using the NCAR reanalysis, comparing December 24 in 1955 with December 24 in 2015. The plots are in Kelvin. It was quite a bit hotter on Christmas Eve this year pretty well everywhere. Notice the polar regions, and the tropics.

The point is...

Whether or not the mean daily temperature on 24 December for the contiguous USA was as warm or nearly as warm as it was this year on 24 December might be interesting if you play Trivial Pursuit. However it tells you next to nothing about the overall warming trend in the USA, or North America, or the entire world. And neither does it detract from the fact that this December has seen some very unseasonal warmth across eastern North America (and much of western Europe, too).

It's been warm in much of the USA

Here is how Bob Henson and Jeff Masters at Wunderground.com described the unseasonal warmth this December:

Hundreds of records were buried by sunshine, warmth, and humidity instead of white-Christmas snowfall all across the eastern U.S. during the holidays, especially on Thursday and Friday. Christmas Day was the apex for the north-south breadth of warmth, with record highs set from Florida (82°F in Jacksonville) to Maine (62°F in Portland). Many records on Thursday and Friday were smashed by margins of 10°F or more. The Christmas Eve readings of 72°F at Albany, NY, and 68°F at Burlington, VT, both set all-time records for December. As noted by WU weather historian Chris Burt, these are truly impressive records given the late date in a month that gets progressively colder, not to mention the long periods of record at both sites (since 1883 in Burlington and 1874 in Albany). Chris adds that Philadelphia has seen eight days this month through Sunday with record daily highs: “Not since records began in Philadelphia back in 1874 has any other month of any single year experienced as many daily record highs as this December!” The capital of Christmas commerce, New York City, basked in record warmth of 72°F on Thursday and 66°F on Friday. As of Sunday, Central Park had yet to get below 32°F this fall or winter; its monthly average (12/1 – 12/26) of 52.0°F was running at an astonishing 13.8°F above normal and 7.9°F above the previous December record, going back to 1871. A cooldown this week will reduce that value, but a warmest-on-record December is all but certain for much of the eastern U.S. It’s no wonder that flowers and shrubs are blossoming from Washington to New York.

Daily records USA

Below is a table from NOAA, listing the daily records broken in the last week and month.

Period

Hi Max

Hi Min

Low Max

Low Min

Precip-itation

Snow-fall

Last 7 Days

1,210

1,412

29

12

534

127

Last 30 Days

3,902

5,364

319

276

2,778

663

Last 365 Days

28,682

40,491

18,527

11,384

29,967

6,874

Month to date

3,879

5,301

166

159

2,572

610

Year to date

28,637

40,425

18,098

11,192

29,881

6,736

The table below shows the number of daily low maxima and low minima as a percentage of the daily high maxima and minima. Over the last week and month, the lows were all less than 10% of the highs. In the last seven days, the number of record low minima was only 0.8% of the record high minima

The chart below shows the number of monthly record low maxima and minima as a percentage of the monthly record high maxima and minima, which in all cases were more than the record lows. In the last seven days, there were no recorded record monthly low minima.

Period

Low Max

Low Min

Last 7 Days

0.0%

0.0%

Last 30 Days

16.1%

3.5%

Last 365 Days

35.6%

21.7%

Month to date

1.8%

0.0%

Year to date

35.1%

21.7%

It's easy to see how unusual the most recent week and month have been. Given global warming, it's not unexpected that there are more high records than low records.

Fewer low minima records than low maxima records

Over the past year for the USA the low maxima average out at around 64% of the high maxima, while the low minima are only around 28% of the high minima.

I've had a look at the literature to see why night time minima would be rising more than daytime maxima. Sometimes I read about how a reduction of the diurnal range of temperature is a sign of global warming, or at least that nights should warm faster than days. After reading up a bit, I discovered that it's not that simple. (An extensive study was done a few years ago (in 2006), which documented changes in extreme temperature (and precipitation) across the world.)

There have been a number of papers on the subject of trends in diurnal temperature range (DTR). The classic paper is from 1999, by Aiguo Dai, Kevin E. Trenberth and Thomas R. Karl - the title is self-explanatory: "Effects of Clouds, Soil Moisture, Precipitation, and Water Vapor on Diurnal Temperature Range". Cloud cover makes a difference. As the authors wrote: "Clouds can reduce Tmax by reflecting the sunlight and increase Tmin by enhancing downward longwave radiation". Clouds are not all the same, though. Different clouds have different effects. Soil moisture and precipitation also make a difference, for example there can be a cooling effect of evaporation at the surface in the daytime, which is less at night.

If you're interested in exploring the subject, I've listed some references below. As I said, it's not straightforward. Here is something to whet your appetite, from the concluding section of Dai99. It's quite long, and you'll probably see why I decided not to try to summarise. It's complicated:

Our analysis of the daily data from the FIFE site and the global weather stations shows that clouds, soil moisture, and precipitation can reduce the surface diurnal temperature range by over 50% compared with clear sky days, while atmospheric water vapor increases both the Tmin and Tmax and has small effects on DTR over most land areas except the northern high latitudes where DTR tends to be larger in high humidity days in winter and autumn. Changes in wind directions, such as those associated with the passing of synoptic systems, can greatly alter the daily mean temperature but generally do not affect DTR significantly at the FIFE site. Clouds, which contribute most of the DTR reduction and largely determine the mean magnitudes of DTR over most regions, reduce DTR by sharply decreasing surface solar radiation and thus the daytime maximum temperature, while soil moisture increases surface latent heat releases and slows down the temperature rise during the day in warm seasons. However, surface sensible heat fluxes tend to offset a large part of the latent heat release anomalies and make soil moisture less effective in damping DTR. Precipitation affects DTR mostly by increasing the soil moisture content while its direct damping on DTR is relatively small. The nighttime minimum temperature is largely controlled by the greenhouse effect of lower atmospheric water vapor, while the daytime maximum temperature depends heavily on the surface solar heating, which is strongly affected by cloud cover, and the amount of it that is released into the air by sensible and latent heat, which depends on soil moisture content. Stronger winds tend to reduce DTR over islands, western Europe, and some other coastal areas, but have a small effect on DTR over most inland areas.

Correlations between the nighttime minimum temperature and total, low, middle, and high cloud amounts are weak in all seasons in low latitudes and in summer in high latitudes. This suggests that, except for the winter high latitudes where solar radiation is at a minimum, the nighttime greenhouse warming effects of clouds tend to balance their daytime solar cooling effects on afternoon temperatures, resulting in small net effects on the nighttime minimum temperature. This further suggests that clouds damp DTR mainly by reducing the daytime maximum temperature over most land areas while their downward longwave radiation contributes little to the DTR reduction mainly because it has a relatively small diurnal asymmetry. Our results are consistent with those of Power et al. (1998), who find that over Australia annual precipitation, which is highly correlated with cloud cover, negatively correlates with Tmax but generally not with Tmin.

Clouds with low bases are found to be most efficient in reducing the daytime maximum temperature and DTR. High and middle clouds have only moderate damping effects on DTR mainly because they are usually optically thinner than clouds with low bases.

The reduction of DTR by clouds is largest in warm and dry seasons (e.g., SON for many northern midlatitude regions such as the United States, southern Canada, and Europe) and smallest in the winter high latitudes where sunshine is largely absent. This is expected because during warm and dry seasons surface latent heat release is limited so that the daytime maximum temperature depends more on the solar heating and thus clouds.

A later paper by Ryan Eastman, Stephen G. Warren and Carole J. Hahn (2011) showed that total cloud cover increased from the middle of last century through to the late 1990s, but then decreased, mostly because of a reduction in low level cloud. Over the same period high clouds increased. That paper also looked at the relationship between cloud cover and sea surface temperature, which was interesting and showed some differences in different parts of the oceans.

In 2012 there was a paper published in 2012 by Ryan G. Lauritsen and Jeffrey C. Rogers, in which they discussed different factors affecting the diurnal temperature range in different regions across the USA. Just as the other papers demonstrated, the relationships are not simple, with different factors dominating in different regions. That is, different regions have different patterns of cloud cover, precipitation, and soil moisture. The diurnal temperature difference can also be affected to some extent by atmospheric circulation teleconnections.

I don't know if there's any consensus about what the future will hold for clouds of different types in different regions. It's hard enough for scientists to figure out cloud cover from observations. (Read this paper by Seiji Kato et al to get an idea of some of the difficulties, and how different estimates of cloud cover will lead to very different estimates of radiative forcing.)

67 comments:

Also the observed trends in the diurnal temperature range have a much higher uncertainty than the trends in the mean temperature. Many reasons for inhomogeneities (many changes in the observational methods) affect the maximum and minimum temperature in the opposite direction. As a consequence, the breaks in DTR are larger than those in the mean temperature. Some examples:

Change in response time of instrument: a very fast thermometer can measure turbulent changes in temperature. A slower instrument would average them away, making the maximum temperature smaller and the minimum temperature larger.

Changes in radiation errors. If radiation can come onto the instrument there will be a (solar) warming bias during the day and an (infra-red) cooling bias during the night.

Changes in location. There are often strong spatial differences in the diurnal temperature range, which for example depends on the distance from water or the amount of vegetation.

Linking to that one picture was clearly deceptive of Andy Wilkins. So stupidly deceptive that I would almost wonder if he is an agent provocateur of Greenpeace.

The other sources do show that it is just one day and a critical reader could thus see that this has nothing to do with climate change, but only illustrates that the weather is quite variable. I hope these warm winters will not again lead people to assume we will never have cold or snowy winters anyone and no longer prepare. Weather will not magically stop in future.

iirc, when climate change became a public issue things used to be phrased in term of "by 2050". Nowadays all that seems far too optimistic: the debate is how much of the extreme weather (and to all too many people that means disasters)right now is down to climate change.

The only thing that seems to be entirely unaffected is the denial. To judge by his concerns, Anthony cannot possibly be living in California anymore.

As interesting as the N.A. temps are, the arctic is simply gone nuts. Longyearbyen, Svalbard: "The warm season lasts from June 15 to September 4 with an average daily high temperature above 41°F. The hottest day of the year is July 23, with an average high of 48°F and low of 42°F."

Current temperature: 43F.

That's insane since considering they haven't seen the sun since October 27th. Two months with no sun and the temps are as high as mid-summer?

Tomorrow thaw at the very north pole.Is this my planet?https://www.washingtonpost.com/news/capital-weather-gang/wp/2015/12/28/freak-storm-in-north-atlantic-may-push-temperatures-70-degrees-above-normal-at-north-pole/

The forecasted temperatures are now evident in the onsite data. Buoy 300234062785480 located at 85.45N rose 25C in 9 hours (and is now above freezing). It was -24.3C at 0600 hours (day 363.25) and +1.0C at 1500 hours (day 363.626).

Hi Sou,Glad to see I've got you thinking!What does all the (admittedly very interesting) above data have to tell me?It tells me that temp differences over the decades are minimal and definitely nothing to worry about.

That is the nub of the problem that AGW proponents have to deal with - the average educated man or woman on the street notices the differences of mere tenths, or even hundredths, of a degree that you complain about and finds hysteria about such tiny differences deeply unimpressive. They also see the kind of nasty weather that you get worried about being no different to the nasty weather they have occasionally experienced throughout their lives.People are far too busy leading their very busy lives to genuinely care about lowering their "carbon footprint" and this is one of the many reasons why CO2 levels continue to rise. Admittedly, there are an extremely small number of people who pay lip-service to the AGW meme by buying a bicycle or putting some extremely expensive and inefficient solar panels on their roof, but they are a mere drop in a huge ocean of people who couldn't care less.

I'm afraid you've lost a battle that nobody else wanted to fight or even cared about. If you were winning the battle CO2 levels would be static or even falling.

Some might accusimg me of trolling - I'm just telling you how it is out in the real world away from the COP junkets and pages of the Guardian.

That will be all I have to say at your site, as I don't want to start a protracted argument that I know will change neither of our minds. I just want to (genuinely) thankyou for listening to what I have to say with good grace and manners.

"It tells me that temp differences over the decades are minimal and definitely nothing to worry about, because temperatures above freezing at the North pole in the middle of the Arctic winter are perfectly normal."

Well we've seen 1, 3, and 4 falsified. But I don't think 2 captures the ignorant superciliousness and baseless superiority held together with a dash of sexism. Probably a bit of giggling in his mind as he typed too.

I'm no longer surprised that there are wilfully ignorant deniers who boast that they are members of the illiterati, and want to harm the world. History going back thousands of years shows that humans are capabable of much good and much evil, and there's undoubtedly always been a bottom 8%.

We educated Men-In-The-Street know that 1.5 is only 0.00015% of one million. Therefore, we laugh at the alarmists who insist that it's unwise to ingest 1.5 milligrams of cyanide per kilogram of body weight.

The temperature point is well made - the majority of people don't understand what it actually means for a rise in temperature of 0.01C globally. I try to instil an understanding of energy in my students so they can see that a temperature rise means an increase in thermal energy in the system. Once you see how much energy is involved, a small global temperature rise no longer looks trivial.

>>"If you were winning the battle CO2 levels would be static or even falling."

CO2 is a well-mixed greenhouse gas. To even get to a steady state of CO2 levels would require an immediate reduction of 70% to 80% of current global emissions from all sources, ie from burning coal, burning oil in motor vehicles, deforestation, cement production and the rest. If we suddenly stopped adding any CO2 to the air, then CO2 levels would drop because it would continue to be absorbed by the ocean and biosphere for as long as it is out of balance. We'd probably have to cut current emissions by more than 80% to see Andy's drop in CO2 levels - and maybe more.

That is quite unrealistic. It won't happen right away it will take several decades, so Andy is misguided at best.

The other thing is, of course, that even when we do get CO2 to a steady state (assuming we are successful in getting that far), then the extra CO2 will still have an effect on climate for thousands of years in the future. The most noticeable effect will be over the coming thousand years or so. The warming that we've already seen is said to be irreversible for generations, but not unstoppable - Damon Matthews and Susan Solomon have written:

"...the warming that has already occurred as a result of past anthropogenic carbon dioxide increases is irreversible on a time scale of at least 1000 years (5, 6). But irreversibility of past changes does not mean that further warming is unavoidable."

This was just posted on Verheggen's blog: http://www.nature.com/nclimate/journal/v4/n3/images/nclimate2148-f1.jpg(below https://klimaatverandering.wordpress.com/2015/12/29/de-wondere-warme-wereld-van-richard-tol/ )

That is the nub of the problem that AGW proponents have to deal with - the average educated man or woman on the street notices the differences of mere tenths, or even hundredths, of a degree that you complain about and finds hysteria about such tiny differences deeply unimpressive.

Educated is one thing, Andy, but you also have to be informed. "Tenths or even hundredths of a degree", eh? How about an anomaly that's currently more than *1 whole deg C* above the 1951 - 1980 baseline! Such a huge increase over such a short time frame represents an astounding amount of energy that we have trapped largely with mankind's CO2 emissions.

Part of the reason the public is so blasé about the AGW issue is that there are plenty of wilfully ignorant (and ideologically motivated) people like you around telling them there's no problem. Hope that makes you feel good about yourself.

Metzomagic, Andy Wilkins is ignoring the fact that millions of people are already aware of the escalating impacts of climate change. Wilkins is simply pulling the blinds down on his view of the world so that he can see only those like-minded folk in his inner circle, and he is extrapolating back out from his funnelled-vision.

Meanwhile, in the real world, the impacts of global warming are expanding out like ripples on a pond, but unlike ripples they are increasing in effect as they radiate from their temporal initiation points. By the time that Wilkins' ilk realise what's coming, there will be tsunamis bearing down implacably on their heads... and on those around them who were frustrated by the inaction that the Wilkins of the world have sowed and nurtured for so long.

"Such a huge increase over such a short time frame represents an astounding amount of energy that we have trapped largely with mankind's CO2 emissions."

My guess is that Andy would say that if you walked outside on two otherwise equal days, but the first is 20˚C and the second is 21˚C, you would hardly notice a difference. This is the thinking of someone who doesn't understand global contexts. I'd bet he thinks that the global temperature difference between glacial periods and interglacial periods is on the order of tens of degrees Celsius.

"...it definitely looks warmer over the U.S. in 1955 than 2015..."...in the midwest, on the 24th of December of the respective years.

Looking [reluctantly] at the archived rejectionists prattle, it seems they are exercised by a claim made somewhere? that Xmas 2015 was warmest ever in the US...however a helpful commenter at No Brains Zone notes that this claim was never made. The misdirection was built from an Accuweather article that forecast the warmest ever Xmas eve "to unfold across the eastern US"...not at all the same claim ,eh?

The axis of stupidity that is Bastardi/Heller/Gosselin holds firm as ever.

"It was warmer on about 2% of the Earth on one day 60 years ago, therefore the observed global warming trend since then is disproven! ...as is, ahem, my natural superiority!"

Why is there even a discussion of this in a global warming blog? The thesis is patently stupid as a scientific question worthy of comment from the get-go. As any "educated man or woman on the street" clearly knows.

You wrote this "He wrote that it was warmer in the US in 1955". I was just pointing out that the very cold region in the graphic that you say countered this but was cut out was not in the U.S. but in Canada. This means he's technically correct. And for this I'm a mug?

Is that what passes for trying to cover up your error, Cam? It looks as if you have a bad case of confirmation bias. I said nothing about "countering". Read the article again, for example this bit. Or this comment, and this.

I was curious enough to check. Yes, Christmas Eve of 1955 set quite a few then-records for maximum temperatures in the central US -- Wichita, KS hit a high of 28.3 °C, nearly 25 °C above normal. However this was a specific weather phenomenon, with much of November and early December of that year being very cold.

Just another cherry-picked point given out of context by the usual suspects.

"1. HIGHLIGHTSDecember 1955 was notable for its many extremes of weather in the United States. The cold of the preceding month continued well into December, but with some amelioration from the record levels reached in the Northwest [1]. In the Southwest, a sharp return to warmer weather resulted in record high temperatures for in some areas."

I said I wouldn't comment again, but I feel I have to say one more thing:The outpouring of vitriol and hysteria from commenters is quite a sight to behold. Sou has been perfectly polite, but the commenters have not, which is a shame.I'll be saving this page, both as digital and hard copies. In years to come it'll be instructive to place it back up on the net to illustrate how deranged some people became about AGW.

"Your response is really stupid..." My god, the vitriol and hysteria - how do we stand it? Calling a spade a spade is neither vitriolic nor hysterical, Andy.

I've commented at WUWT and Goddard's and read many other threads where I didn't comment. In the realm of vitriol and hysteria this site is *nothing* compared to the treatment even respected scientists often receive there.

If you choose to post a wheedling tone comment instead of seriously addressing the criticisms and points raised about your "cut and pastes" then you should expect some derision. It is hardly hysteria and bile.

Try engaging with the discussion. You might be surprised at how you might start to examine critically what you are promoting.

I think it's been obvious for a while that Andy Wilkins is a denialist troll who will never post anything better than horrible garbage. He even bragged trollishly in the previous post of his 'starring role' in this one. Please banish him to the HotWhoppery, Sou.

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All you need to know about WUWT

WUWT insider Willis Eschenbach tells you all you need to know about Anthony Watts and his blog, WattsUpWithThat (WUWT). As part of his scathing commentary, Wondering Willis accuses Anthony Watts of being clueless about the blog articles he posts. To paraphrase:

Even if Anthony had a year to analyze and dissect each piece...(he couldn't tell if it would)... stand the harsh light of public exposure.

Definition of Denier (Oxford): A person who denies something, especially someone who refuses to admit the truth of a concept or proposition that is supported by the majority of scientific or historical evidence.
‘a prominent denier of global warming’
‘a climate change denier’

Alternative definition: A former French coin, equal to one twelfth of a Sou, which was withdrawn in the 19th century. Oxford. (The denier has since resurfaced with reduced value.)